In many situations where it is necessary to cut, thread, bend or weld an elongate pipe in the field, it is necessary to hold the pipe to prevent rotation during the operation. One tool which is effectively used is a chain vise. As its name implies, the chain vise applies a chain about the pipe so as to clamp the pipe in the vise. Tightening of the chain around the pipe causes frictional engagement therewith so as to prevent movement or rotation of the pipe during the operation.
In certain situations, especially where PVC or other non-metallic pipe is used, the chain vise, by applying tightening pressure directly to the pipe, may have a tendency to damage the surface of the pipe.
In certain situations, especially where PVC or other non-metallic pipe is used, the chain vise, by applying tightening pressure directly to the pipe, may have a tendency to damage the surface of the pipe.
The art has seen the use of half-shell clamps which are placed about the pipe and serve to support the chain of the chain vise. These half-shell clamps prevent direct contact between the chain of the chain vise and the pipe surface. One problem associated with certain half-shell clamps is that the clamps slip with respect to the pipe. Attempts to increase the friction between the half-shell clamps and the pipe, such as placing score marks on the internal surface of the half-shell clamps, result in ineffective gripping power and/or increased damage to the surface of the pipe.
It is, therefore, desirable to provide half-shell clamps for placement about a pipe so as to accommodate a chain of chain vise.